Electrical clinometer



April 23, 1957 A. M. MAROTH 2,789,362

' ELECTRICAL CLINOMETER Filed nec. 22, 195s /o |36 8 .www

v JNVENTOR. iff/wx M /Vqforf/ Iof ythe spirit tube.

ELECTRICAL CLINOME'IER Arthur M. Maroth, Wilton, Conn.

Application December 22, 1955, Serial No. 554,696

9 Claims. (Cl. 3.3-206) The 'present invention relates generally to anelectrical clinometer, that is, an instrument for indicating or checkingthe level or angle of a slope, elevation or inclination.

"Heretofore, clinometers have usually comprised two straight armspivotally connected at one end and associated Iwith a protractor forindicating the angle included between the arms, and a spirit tubeembodied in =one of the arms so that, when the other arm is appliedagainst the slope to be measured and the arms are angularly adjusted tocenter the bubble of the spirit tube between the usual index lines, theprotractor will then indicate the angle of the slope. With such anarrangement, the accuracy of the indication depends uponpthe -ability ofthe user to effect absolute centering of the lbubble of the spirit tubebetween the index lines by :angular adjustment of the arms, whichrequires a clear :and unobstructed view of the spirit tube. However,

,the slope to be measured frequently is in a location that `eitherprevents or makes difficult the required viewing Further, the areaaround the slope 4to be measured may be crowded and thereby preventangular adjustment of the arms of the clinometer, par- :ticularlyto theextent necessary for the measurement' of large angles of slope orinclination.

Accordingly, it is an object of the present lnvention :to provide` anelectrical clinometer for indicatingY orf Lchecking the level or angleof a slope, elevation or- `inclination, and that furnishes an easilyobserved signal, for example, the illumination of a light bulb, onlyjlwhenthe setting and indication of the electrical clinometer lexactlycorrespond to the level or angle of the slope being checked or measured.

Another Objectis to prov1de an electrical clinometer, of increasedaccuracy, and that facilitates the adjustnient thereof for the checkingor measurement of different slopes or inclinations.

In 'an aspect of the invention an electrical clinometer includes agenerally rectangular, elongated casing adapted to be .applied againstthe surface to be checked or measured, a reservoir Within the casing forcontaining a body of electrical conducting liquid, for example, mercury,having a free surface, an electrical circuit including a source ofelectricalcurrent, a signal, for example, a light bulb, and two contactsdisposed adjacent the, free surface of the body of electrical conductingliquid to complete the circuit forenergizing the signal only when bothcontacts are simultaneously immersed in the liquid by the conforming ofthe surface ofthe liquid with a line passing through both contacts, avrockable support for the contacts so that the angle between. thelongitudinal axis of the casing and theline passing-through bothcontactscan be varied, mechanism for-rocking vthe Contact support,vandindicating means associatedlwith such mechanism and suitably calibratedto indicate the angle included between the'line passing throughthecontacts 'and the longitudinall axis of the casing. Vi

The above, and other objects, features and advantages 2,789,362 PatentedApr. 23, 1957 Mice Fig. 3 is a horizontal sectional view taken along theline 3--3 of Fig. 2; f

Fig. 4 is afragmentary, vertical-sectional view taken along the line 4-4of Fig. 2; and

Fig. 5 is a wiringdiagram representing an electrical circuit included inthe illustrated clinometer.

Referring tothe drawing in detail, and ,initially to` 12 and is disposedwith its central Aaxis lying in a plane,

that -is parallel to theilatbottom surface 14 of the casing andextendingtransverselywith respect tothe longitudinal axis of the casing 1,2. Asseen in Fig. 3, the reservoir 16 preferably hask a bulbous peripheralportion 18 connecting together the outer edges of relatively closelyspaced apart parallel side walls 20 which have hubs 22 at ,the centersthereof. The reservoir 16 is adapted to contain a body 24 of` electricalconducting liquid, for example, mercury or any other suitable conductingliquid, occupying one half of the interior volume of the reservoir,.sothat the body of liquid 24 has a freesurface 26 at a level passingthrough the center of the reservoir.

It is apparent that,.when the bottom surface 14 -of the casing 12extends horizontally, the free surface26 of the electrical conductingliquid will be parallel to the bottom surface of the casing, andthat, asthe bottom surface 14 is inclined relative to the horizontal, the freesurface 26 remains horizontal and the angle includedV between the freesurface of the bodyv of electrical conducting liquid and the bottomsurface 14 ofthe casing .will be equal to the inclination of the casing.

vA shaft 28 is rotatably journaled in the hubs 22 of the reservoir 16,and suitable packing glands 30 are provided in the hubs to preventleakage ofthe electrical conducting liquid 24 from the reservoir aroundIthe rotatable shaft 28. Arms 32 and 34 extend radially,

.free ends of the arms 32 and 34, respectively, and are aranged so thata line drawn from the tip of contact point 36 to the tip of contactpoint 3 8 will pass through the axis of rotation of the shaft 28. Thus,the tips of the contactpoints 36 and 38-wi1l engage the free surfaceV.w26 of the electrical conducting liquid only when the shaft 28 isrotatably disposed with respect to the casing 12 so that the linepassing through the tips of the contact points and the axis of the shaft28 lies in the horizontal plane of the surface 26. The contact points 36and 38 may be formedof carbon, silver or the like'to preventelectrolysis resulting from their intermittent contact with' the'body ofelectrical conducting liquid. yThe arms 32 and 34 are preferably alsoformed of `an electrical conducting material and are insulated from eachother,

jat the shaft 28, where conductors 40 andV 42 are re.

spectively connected 'to the arms "32 and 34.

3 Thexcontact points,36 andi38 cooperate with the fr? ,Suffe 26 ofthebody 0f ,electrical..ccnsuctins.

liquid to control the opening and closing of an electrical circuit forenergizing a. signal device included in the clinometer 10. In the`illustrated*embodiment,oftheA invention, the signal deviceisVrepresentedl by ,a light bulbV 44 received `in a -suitable receptacle46r` at ,one end of the( casing l2nand projecting y from thelatterwithinjaq Suitabliy Protects@ domed class.` Cover 48- The, cume ofcurrent for energizinglthe ligligtfbullrll,4 is preferably in the lformof audry cellbatterypack" Si) which is @unt-@d in -a .SlitelzlSuPPQrt,5,2 ,Within the. Casing' 12 and can beinsertedjanrd removedn 'throughan .opening at,l ytheve'nd Yof .the Y ca singwr and normally closed by acover plate 541,'

As seen particular-ly'inFig. 5,y the, electrical circuit for Yenergizingthe light lbulb` 44 may have the Y.conductor 42.connect ed toloneterininal ofV-thebattery pack .'50,

whilehe conductor ,'40 isconnectedto the central ycron-. v

tact of theflighthnlbreceptacle, 46; Y Further,fa-con ductor 56extendsbetween. thebas-e4 orshell of vthe re-,j ceptaclfe t6-andthe otheruterminal'ffthe battery:.pael. and preferablfhas vanhn-ff toggleswitchrfSSA interposed.; therein so, that the, lightbulb can bevenergizd V.onlyl` when the contactsvof the switch ,58m-e"closedandbothAcontact points36and 38 ,simultaneously engage free A surface 26 ofthebody 24 Aof conducting liquid Assuming that theshaft 28 isurotatablyudisposed so that the liney extending through the ltips of bothv contactpoints v36 and 38 is parallel tothebottomfsuface 14 of the casing, itis'apparent that'the vcircuit for'energizingu the bulb 4 4.will beVcompleted through .the contactpoints and the body 24 of conductingliquid 'onlyfwhenthe surface 14 of the casinglies in afhoriz'ontalplane.'

With such, a setting` of the shaft 28 and Contact points'. 36 and 38,which corresponds .to the use Vof the.` cli?l nometer as a level,inclination of the bottom surface .14

of the' casingV will similarly incline the llinefpassing. `throughrthetips of both contactpoints, whi'lethe freek surface 26 oftheconductin'g'liquid remains horizontal,

so that r one or.the other ofthe contact points will`beV spaced from thesurface 26 to interrupt the Yelectrical energizing circuit of the lightbulb 44,.

lf theshaft 28 is angularly adjusted relativeA to the casingr12 so thata predetermined angle Ais included bel,` tween the tlat bottomsurface`14 and the line passing through the tips of the contact points36 andf38, the latter'w'ill simultaneouslyrengage the free surface ,26,off,I the `conducting liquidft'o complete theelectrical yenen4 gizingcircuit of the 4light bulb"`44 only Whllfthelbob torn surface: 14 ofthe'casingisinclined lrelativefto" the horizontal byy the samepredetermined angle. `In ac co'r'danceY with the present invention,-mechanism"pro-` vided for angularlyadjusting the shaft`28f is opertively associated with 'an arrangement indicating,y at all tir'nes',y

theY angle included betweenfthe flattbott'nm surface 4f passing throughthe't'ips'v Vofl of the casing and. the line theA contact points n 36Land 3S.

In the illustrated embodiment of the invention, the

mechanism forangularly adjusting the shaft 28 includ-esv a worm gear 60xed on the shaft 28 and meshing withY a worm 62 on a drive shaft641th'at extends longitudinally within thedcasing 12 and projects fromthe. endfof the latter remote from ther light bulb 44. A lknurledk 1 and`4)F so that the follower nut 70is held-against ro tation andmovesaxially along the worm 68 in response to rotation @Hhs drivejshat ,641''feerelzlnjffiapitea- Ote fremthe lishtfbulbt afaasee of the worm 68 issubstantially greater than the Jpitch ofhewonn 62 .so that, arelatively. small. .ansular.. 1i;- placement of the shaft 28 and thecontact points 36 and 38 will be accompanied by a relatively largelinear displacement of the follower nut 70. A scale 78, calibrated indegrees, is provided on the side wall 76 of the casing along the slot 74and cooperates with a Vernier index 80 formed by a flangeon the freeedge of the extension 72 and having Vernier gradua'tions, not shown. Thefollower nut 70` is arranged on the worm 68 so that, when the vernier80is centered along theslot 74, as in Fig. 1, the shaft 28 and contactpointsl`36 and 38 are angularly ldisposed vwith the ,linepassingthrough; the tips of the contact points being parallel to the surface 14of th-e casing. It is' apparent that, as` the shaft 64 is rotated in onedirection or the other to incline the line yextending through the tipsof Contact points 36 and 38 with respect to the surface 14, the Vernierindex 80 will move `,along the scale 78 and cooperate withthe latter.lto indicate the extent of such inclination.

When the clinometer 10 is Vto beemployed -as a level, theknob k66 .isrotated `until the `Vernier index 8() isopposite the` indication forzero degrees on the scale 78.j Then, the light bulb 44 will beilluminated only whenu the surface,` against which the bottom surface14yis Vapplied, is horizontally disposed. measure ,the angle of aninclination, or slope, ythe sur-` face 14is applied against the slopeand the knob is rotated until the light bulb is illuminated, whereuponthe clinometer, theillumination of the light bulb 44clearlyandraccurately indicates when the casing is disposed either l levelfrorat the desired angle to the horizontal, so that,

there is no necessity to closely observe the condition of a.,VA

spirittube, as in previous clinometers. Further, the clinometerembodying the present invention is easily Aatl-y justablel and, in viewof the relatively Igreat pitch.y ofthe*i worm 68, provides an expandedscale that can beac-.

curately read, even when working in close or crowded, locations.

It", is falso. to be notedthat, by reason :of .the relatively; greatdistance between the contact points 36, ancl-3,8, 5a.

sli ghtv angular `displacement of Athe contact points rfelative lrelatively v,large vdisplacement of the contact pointshin'htheidirections generally normal Ato the surface 26 therebywinf creasingithesensitivity and accuracyof` theindcatipnf Fr'therfthefdes'cribedconli'gurationf of thereservoir 16. tendsito ,accumulate arnajor portionof the Vbody of liquid- 24 'rwithinlthe Vbulbous Vperipheral'portion 18of theres-f ervoirfor cooperationr with the contact points 36 andp38 y,thereby reducing, the" volume of mercury required, as, compared-witha'cir'cular reservoir of `uniform cross-sec; tion,v so that the effectsof inertia on the body ofconductingliguid kare correspondingly. reducedto ensure thatfthy freefsurface 26 will'readily remain horizontalas,the1.

casing12 is angularly displaced.

Although an illustrative embodiment of theinvent'ion: has been describedin detail herein and shown in the ,ac-v

companying` drawing, it is tobenunderstoodthat the invention is notlimited to that precise embodiment, and that. various changes`and.modifications may v,be effected,

in the-latter withoutk departing vfrom ,the scripeorspirit'v oftheinvention as defined in the appended claims.v`

What is claimed is:

1. A clinometer or the like for determining .theV angle 0f .e 8.19m.,:werden .as castes .beting .a Straight 19net.??

If it is desired to,

Then, theH reservoir in said casing containing a body of electricalvconducting liquid having a free surface which remains horizontal assaid surface of the casing is angularly displayed from the horizontal,an electrically operated signal device, an electrical circuit foroperating said signal device and having contact points interposedtherein and cooperating with said body of electrical conducting liquidso that said circuit is completed and said signal device is therebyoperated only when said contact points simultaneously engage saidfreesurface of the liquid, adjusting means operative to angularly displacesaid contact points with respect to said surface of the casing therebyto vary the inclination of the casing at which said contact pointssimultaneously engage the free surface of the liquid, and indicatingmeans responsive to said adjusting means and operative to indicate theinclination of said surface of the oasingvat which said contact pointswill simultaneously engage the conducting liquid and cause operation ofsaid signal device.

2. A clinometer or the like for determining the angle of a slope;comprising a casing having at n least one straight longitudinal surfaceadapted to be applied .against the slope to be measured, a reservoir insaid casing containing a body of electric conducting liquid having afree surface, two contacts movable in a longitudinal plane that isperpendicular to the plane of said straight longitudinal surface of thecasing and being disposed symmetrically at opposite sides of thetransverse medial line of said free surface of the liquid on a linepassing through said transverse medial line so that said contactssimultaneously engage said free surface only when said line through thecontacts lies in the plane of said free surface, an electricallyoperated signal device, an electrical circuit for operating said signaldevice and having said contacts interposed therein so that said circuitis completed through said body of electrical conducting liquid only whensaid two contacts simultaneously engage said free surface of the liquid,and means operative to move said contacts oppositely about saidtransverse medial line of the free surface thereby to vary the angularrelationship between said line through the contacts and said straightlongitudinal surface of the casing for determining the angle of saidstraight surface of the casing from the horizontal at which saidcontacts will simultaneously engage the free surface of the liquid andcause operation of said signal device.

3. A clinometer or the like for determining the angle of a slope;comprising a casing having at least one straight longitudinal surfaceadapted to be applied against the slope to be measured, a reservoir insaid casing containing a body of electrical conducting liquid having afree surface, two contacts movable in a longitudinal plane that isperpendicular t-o the plane of said straight longitudinal surface of thecasing :and being disposed symmetrically at opposite sides of thetransverse medial line of said free surface of the liquid on a linepassing through said transverse medial line so that said contactssimultaneously engage said free surface only when said line through thecontacts lies in the plane of said free surface, an electricallyoperated signal device, an electrical circuit for operating said signaldevice and having said contacts interposed therein so that said circuitis completed through said body of electrical conducting liquid only whensaid two contacts simultaneously engage said free surface of the liquid,means operative -to move said contacts oppositely about said transversemedial line of the free surface thereby to vary the angular relationshipbetween said line through the contacts and said straight longitudinalsurface of the casing for determining the angle of said straight surfaceof the casing lfrom the horizontal at which said rcontacts willsimultaneously engage the free surface of the liquid and cause operationof said signal device, and indicating means -responsive to said meansmoving the contacts and openative to show the angle of said straightsurface ofthe casing relative to the horizontal at ywhich operation ofsaid signal device will occur.

4. A clinometer or the like for determining the angle of a slope;comprising a casing having at least one straight' longitudinal surfaceadapted to be applied against the slope to be measured, a generallycircular reservoir insaid casing disposed with its central axisextending paral-y lel kto the planeV of said surface of the casing andtransversely with respect to the latter, a body 'of electricalconducting liquid half-filling said reservoir so that the center of thelatter lies in the free surface of the liquid,

two contacts at diametrically opposed locations in said reservoir andmovable together about the central axis Y of the latter` so that saidcontacts simultaneously engage said free surface of the conductingliquid only ,when thel diametrical line extending through both contactsis hori zontally disposed, an electrically operated signal device onsaid casing, an electrical circuit for operating said signal device andhaving said contacts interposed therein so that the circuit is completedthrough said body ofv electrical conducting liquid only when saidcontacts simultaneously engage said free surface of the liquid, and

means for angularly adjusting said contacts about said central axis ofthe reservoir thereby to vary the angle of said straight longitudinalsurface of the casing relative to` the horizontal at which said signaldevice is operated.

5. A clinometer or the like for determining the angle of a slope;comprising a casing having at least one straight longitudinal surfaceadapted to be applied -against the lslope to` be measured, a generallycircular reservoir `in said casing disposed with its central axisextending parallel .to Athe lplane of said surfaceiof the casing andtransl versely with respect to the latter, a body of electricalconducting liquid half-filling said reservoir so that the center of thelatter lies in the free surface of the liquid, two contacts atdiametrically opposed locations in said reservoir and movable togetherabout the central axis of the latter so that said contactssimultaneously engage said free surface of the conducting liquid onlywhen the diametrical line extending through both contacts ishorizontally disposed, an electrically operated signal device on saidcasing, yan electrical circuit for operating said signal ldevice andhaving said contacts interposed therein so that the circuit is completedthrough said body of electrical conducting liquid only when saidcontacts simultaneously engage said free surface of the liquid, meansfor angularly adjusting said contacts about said central axis of thereservoir thereby to vary the :angle of said straight longitudinalsurface of the casing relative to the horizontal at which said signaldevice is operated, and indic-ating means responsive to said 'angularadjusting means to show the angle included between said straightlongitudinal surface of the casing and the diarnetrical line throughsaid contacts, thereby indicating said acngle of said straightlongitudinal surface relative to the horizontal at which said signaldevice is operated.

6. A clinometer or the like for determining the angle of a slope;comprising a casing having at least one straight longitudinal surface`adapted to be applied against the slope to be measured, a generallycircular reservoir in said casing disposed with its central axisextending parallel to the plane of said surface of the casing andtransversely with respect to the latter, a body of electrical conductingliquid half-tilling said reservoir so that the center of the latter liesin the free surface of the liquid, two contacts at diametrically opposedlocations in said reservoir .and movable together about the central axisof the latter so that said contacts simultaneously engage said freesurface of the conducting liquid only when the diametrical lineextending through both con-v tacts is horizontally disposed, anelectrically operated signal device on said casing, 'an electricalcircuit for operating said signal device and having said contacts,interposed therein so that the circuit is completed through weer@meansrflol angu1arly`displacing said shaft about the latters` Y 4thereby tr vary the angulark relationshipV of, said, straightlongitudinal surface of the casing relative to the hciry'izoiital atwhich operation of said signaltdeviceoccurs;

7. A vclinometeror thelike for determining the angle of ayslope@comprising la casing havingvat'least one straightV longitudinalsurface adapted to be lapplied against thelslope, to beI measured, agenerallycircular reservoir inus'aidcasing disposed with itsrcentralfaxis extending` parallelifto the'plane of isaid surface of thecasinganclfY transversely with respect tothe latter,V a body ofelectricalv coiv ting liquid .half-filling said reservoir so that thecenter ofnftheA latter liesin the' 'free surface of the liquid,ltw'oicontactsn at diametrically opposed locations in said reservoir `andmovable together abouttthe central axis of lthe'latter so that saidvcontacts ysimultaneously engage said` yfree surface `of the conductingliquidYonly-When ,the y diainetrical lineV extending through bothcontacts Vis hor-t izontally disposed, an electrically operated signaldevicekv onsaidcasing, an electrical circuitforoperating saidsignal`deviceandhaving'fsaid contacts interposed therein sothat ,fthetci'rcuitgiscornpleted through said body of electricalcdiiduetirig'liquid only when said contacts simultaneously iengagelsaidfree surfacel of the liquida shaft rotatable coaxiallygwiththe central axis of said reservoir and havingv radial garmszextendingtherefrom and carrying said con-n tacts,;'a .worm gearon said shaft, l,amanuallyrotatable i drive lshaft journaied insai'l casing2 a rstworm onsaid Y L withfsaidworm gear to transmitlthel" rotation offsaiddrivejshaftfto said shaft'car'rying the drive shaft 'mesh'i contacts,` avsecond worm on said driveV4 shaft, a follower engaging saidi'sreconvdworm to move axially in responseto rotation of jsaid*,drive `shaft aVscale on said casing calibrated in. degrees and extending parallel to`the axis of said drivesha'ft', andan index carried by said followerl andcooperating With ls'aid scale to indicate-the angular relationship ofsaidfstraight longitudinal surface of the` casing' to the -horizontal/watv which ,said signal deviceis operated.

8.` Av clinonieten or thelike asin claim 7; wherein said second` worrnhasga pitch substantially greater than the pitch ot jsaidirst worm sothat rotation ofsaid` drive shaft througha pr'edeterminedangle willeffect a relatively small angular displacement'of saidcontacts and arelatively large lin-ear movement `of s'aid index along the scale,whereby the latter 4can be longitudinally expanded for easy and accuratereading of the indication given thereby.

9. A clinorneter or the like as in claim 7; wherein said reservoirhasyrelatively closely spaced` apart side walls between which said arnis`extend and a bulbous outer peripheral portion containing a substantialmajor portion of the Ibody of :electricalfconducting liquid contained inthe reservoir, said contacts being engageable with said free, surface of.the liquid in said bulbous peripheral portion of thel reservoir'.

Referencresipted in theglc of this patent FOREKxlSLv PATENTS

